someone pls help

Help with this please

Hi guys, i have few questions which i am unable to solve, i would appreciate if someone could help me .
Question) A music store sells an avg of 160 cds/wk at $24ech. the cost of producing x music cds is c(x)=-0.003x2+4.2x+1000. a market survey indicates that for each 50cents decrease in price,two additional cds will be sold per week.

a)determine the demand,or price,function

b)what is the price of each cd when 170 are sold weekly and when 200 are sold weekly?

c)determine the revenue function

d)which of the following results in greater revenue: the sale of 170 cds or the sale of 200 cds?justify your answer.

e) determine the profit function.

f)which of the following results in a greater profit:the sale of 170 cds or the sale of 200 cds?